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    <title>Earthquakes with custom symbols</title>
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          <h4 id="title">Earthquakes with custom symbols</h4>
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          <p id="shortdesc">Demonstrates the use of &#x60;ol.render.toCanvas&#x60; to create custom icon symbols.</p>
          <div id="docs"><p>This example parses a KML file and renders the features as a vector layer.  The layer is given a <code>style</code> that renders earthquake locations with a custom lightning symbol and a size relative to their magnitude.</p>
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          <div id="api-links">Related API documentation: <ul class="inline"><li><a href="../apidoc/ol.Map.html" title="API documentation for ol.Map">ol.Map</a></li>,<li><a href="../apidoc/ol.View.html" title="API documentation for ol.View">ol.View</a></li>,<li><a href="../apidoc/ol.format.KML.html" title="API documentation for ol.format.KML">ol.format.KML</a></li>,<li><a href="../apidoc/ol.geom.Polygon.html" title="API documentation for ol.geom.Polygon">ol.geom.Polygon</a></li>,<li><a href="../apidoc/ol.layer.Tile.html" title="API documentation for ol.layer.Tile">ol.layer.Tile</a></li>,<li><a href="../apidoc/ol.layer.Vector.html" title="API documentation for ol.layer.Vector">ol.layer.Vector</a></li>,<li><a href="../apidoc/ol.render.html" title="API documentation for ol.render">ol.render</a></li>,<li><a href="../apidoc/ol.source.Stamen.html" title="API documentation for ol.source.Stamen">ol.source.Stamen</a></li>,<li><a href="../apidoc/ol.source.Vector.html" title="API documentation for ol.source.Vector">ol.source.Vector</a></li>,<li><a href="../apidoc/ol.style.Fill.html" title="API documentation for ol.style.Fill">ol.style.Fill</a></li>,<li><a href="../apidoc/ol.style.Icon.html" title="API documentation for ol.style.Icon">ol.style.Icon</a></li>,<li><a href="../apidoc/ol.style.Stroke.html" title="API documentation for ol.style.Stroke">ol.style.Stroke</a></li>,<li><a href="../apidoc/ol.style.Style.html" title="API documentation for ol.style.Style">ol.style.Style</a></li></ul></div>
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          <textarea class="hidden" name="title">Earthquakes with custom symbols</textarea>
          <textarea class="hidden" name="description">Demonstrates the use of &#x60;ol.render.toCanvas&#x60; to create custom icon symbols.</textarea>
          <textarea class="hidden" name="js">var symbol &#x3D; [[0, 0], [4, 2], [6, 0], [10, 5], [6, 3], [4, 5], [0, 0]];
var scale;
var scaleFunction &#x3D; function(coordinate) {
  return [coordinate[0] * scale, coordinate[1] * scale];
};

var styleCache &#x3D; {};
var styleFunction &#x3D; function(feature) {
  // 2012_Earthquakes_Mag5.kml stores the magnitude of each earthquake in a
  // standards-violating &lt;magnitude&gt; tag in each Placemark.  We extract it from
  // the Placemark&#x27;s name instead.
  var name &#x3D; feature.get(&#x27;name&#x27;);
  var magnitude &#x3D; parseFloat(name.substr(2));
  var size &#x3D; parseInt(10 + 40 * (magnitude - 5), 10);
  scale &#x3D; size / 10;
  var style &#x3D; styleCache[size];
  if (!style) {
    var canvas &#x3D;
        /** @type {HTMLCanvasElement} */ (document.createElement(&#x27;canvas&#x27;));
    var vectorContext &#x3D; ol.render.toContext(
        /** @type {CanvasRenderingContext2D} */ (canvas.getContext(&#x27;2d&#x27;)),
        {size: [size, size], pixelRatio: 1});
    vectorContext.setStyle(new ol.style.Style({
      fill: new ol.style.Fill({color: &#x27;rgba(255, 153, 0, 0.4)&#x27;}),
      stroke: new ol.style.Stroke({color: &#x27;rgba(255, 204, 0, 0.2)&#x27;, width: 2})
    }));
    vectorContext.drawGeometry(new ol.geom.Polygon([symbol.map(scaleFunction)]));
    style &#x3D; new ol.style.Style({
      image: new ol.style.Icon({
        img: canvas,
        imgSize: [size, size],
        rotation: 1.2
      })
    });
    styleCache[size] &#x3D; style;
  }
  return style;
};

var vector &#x3D; new ol.layer.Vector({
  source: new ol.source.Vector({
    url: &#x27;https://openlayers.org/en/v4.4.2/examples/data/kml/2012_Earthquakes_Mag5.kml&#x27;,
    format: new ol.format.KML({
      extractStyles: false
    })
  }),
  style: styleFunction
});

var raster &#x3D; new ol.layer.Tile({
  source: new ol.source.Stamen({
    layer: &#x27;toner&#x27;
  })
});

var map &#x3D; new ol.Map({
  layers: [raster, vector],
  target: &#x27;map&#x27;,
  view: new ol.View({
    center: [0, 0],
    zoom: 2
  })
});
</textarea>
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          <textarea class="hidden" name="html">&lt;div id&#x3D;&quot;map&quot; class&#x3D;&quot;map&quot;&gt;&lt;/div&gt;
</textarea>
          <input type="hidden" name="resources" value="https://openlayers.org/en/v4.4.2/css/ol.css,https://openlayers.org/en/v4.4.2/build/ol.js">
          <input type="hidden" name="data">
        </form>
        <pre><code id="example-source" class="language-markup">&lt;!DOCTYPE html&gt;
&lt;html&gt;
  &lt;head&gt;
    &lt;title&gt;Earthquakes with custom symbols&lt;/title&gt;
    &lt;link rel="stylesheet" href="https://openlayers.org/en/v4.4.2/css/ol.css" type="text/css"&gt;
    &lt;!-- The line below is only needed for old environments like Internet Explorer and Android 4.x --&gt;
    &lt;script src="https://cdn.polyfill.io/v2/polyfill.min.js?features=requestAnimationFrame,Element.prototype.classList,URL"&gt;&lt;/script&gt;
    &lt;script src="https://openlayers.org/en/v4.4.2/build/ol.js"&gt;&lt;/script&gt;
  &lt;/head&gt;
  &lt;body&gt;
    &lt;div id&#x3D;&quot;map&quot; class&#x3D;&quot;map&quot;&gt;&lt;/div&gt;
    &lt;script&gt;
      var symbol &#x3D; [[0, 0], [4, 2], [6, 0], [10, 5], [6, 3], [4, 5], [0, 0]];
      var scale;
      var scaleFunction &#x3D; function(coordinate) {
        return [coordinate[0] * scale, coordinate[1] * scale];
      };

      var styleCache &#x3D; {};
      var styleFunction &#x3D; function(feature) {
        // 2012_Earthquakes_Mag5.kml stores the magnitude of each earthquake in a
        // standards-violating &lt;magnitude&gt; tag in each Placemark.  We extract it from
        // the Placemark&#x27;s name instead.
        var name &#x3D; feature.get(&#x27;name&#x27;);
        var magnitude &#x3D; parseFloat(name.substr(2));
        var size &#x3D; parseInt(10 + 40 * (magnitude - 5), 10);
        scale &#x3D; size / 10;
        var style &#x3D; styleCache[size];
        if (!style) {
          var canvas &#x3D;
              /** @type {HTMLCanvasElement} */ (document.createElement(&#x27;canvas&#x27;));
          var vectorContext &#x3D; ol.render.toContext(
              /** @type {CanvasRenderingContext2D} */ (canvas.getContext(&#x27;2d&#x27;)),
              {size: [size, size], pixelRatio: 1});
          vectorContext.setStyle(new ol.style.Style({
            fill: new ol.style.Fill({color: &#x27;rgba(255, 153, 0, 0.4)&#x27;}),
            stroke: new ol.style.Stroke({color: &#x27;rgba(255, 204, 0, 0.2)&#x27;, width: 2})
          }));
          vectorContext.drawGeometry(new ol.geom.Polygon([symbol.map(scaleFunction)]));
          style &#x3D; new ol.style.Style({
            image: new ol.style.Icon({
              img: canvas,
              imgSize: [size, size],
              rotation: 1.2
            })
          });
          styleCache[size] &#x3D; style;
        }
        return style;
      };

      var vector &#x3D; new ol.layer.Vector({
        source: new ol.source.Vector({
          url: &#x27;https://openlayers.org/en/v4.4.2/examples/data/kml/2012_Earthquakes_Mag5.kml&#x27;,
          format: new ol.format.KML({
            extractStyles: false
          })
        }),
        style: styleFunction
      });

      var raster &#x3D; new ol.layer.Tile({
        source: new ol.source.Stamen({
          layer: &#x27;toner&#x27;
        })
      });

      var map &#x3D; new ol.Map({
        layers: [raster, vector],
        target: &#x27;map&#x27;,
        view: new ol.View({
          center: [0, 0],
          zoom: 2
        })
      });
    &lt;/script&gt;
  &lt;/body&gt;
&lt;/html&gt;</code></pre>
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